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Sem

Sem is an MCP server that adds developer tools to AI assistants such as Claude Desktop, Claude Code and Cursor. Entity-level code intelligence: semantic diff, impact analysis, blame, and context for AI agents. It has 3,425 GitHub stars, is released under the Apache-2.0 license and runs locally with npx -y @ataraxy-labs/sem.

github.com/Ataraxy-Labs/sem (opens in a new tab)

Data as of from the GitHub API and the official MCP registry; description from the project's repository. Report an error

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Install Sem

Generated from the server's MCP registry entry. Replace your-value with your own values.

Claude Desktop

claude_desktop_config.json
{
  "mcpServers": {
    "sem": {
      "command": "npx",
      "args": [
        "-y",
        "@ataraxy-labs/sem"
      ]
    }
  }
}

Settings > Developer > Edit Config. macOS: ~/Library/Application Support/Claude/, Windows: %APPDATA%\Claude\. Restart Claude Desktop afterwards.

Claude Code

claude mcp add --transport stdio sem -- npx -y @ataraxy-labs/sem

Cursor

.cursor/mcp.json
{
  "mcpServers": {
    "sem": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@ataraxy-labs/sem"
      ]
    }
  }
}

Project file; use ~/.cursor/mcp.json to enable it in every project.

VS Code

.vscode/mcp.json
{
  "servers": {
    "sem": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@ataraxy-labs/sem"
      ]
    }
  }
}

Config formats checked against the official docs on Oct 7, 2026: modelcontextprotocol.io (opens in a new tab), code.claude.com (opens in a new tab), cursor.com (opens in a new tab), code.visualstudio.com (opens in a new tab).

About Sem

Part of the Ataraxy Labs stack: agent-native infrastructure for software development. See also: weave (entity-level git merge driver) · inspect (semantic code review) · opensessions (tmux sidebar for coding agents).

  • ai-agents
  • developer-tools
  • git
  • semantic-diff
  • tree-sitter
  • code-intelligence
  • coding-agents
  • llm-tools
  • typescript
  • version-control

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FAQ

Sem FAQ

Still curious? Email info@appsgit.com.

How do I install the Sem MCP server?

Add the command npx -y @ataraxy-labs/sem to your MCP client: put it in claude_desktop_config.json for Claude Desktop, run claude mcp add for Claude Code, or add it to .cursor/mcp.json (Cursor) or .vscode/mcp.json (VS Code). The snippets on this page are ready to paste.

Is Sem free?

The server is open source under the Apache-2.0 license, so running it is free. It does not declare any required API key.

Is Sem actively maintained?

The most recent commit was on Oct 26, 2026. The latest release is v0.28.2, published Oct 26, 2026. appsgit only lists MCP servers with a commit in the last six months.